Computed tomography (CT) is a technology that makes use of computer-processed combinations of X-ray images taken from different angles to produce cross-sectional images. The CT technology has been widely used in medical diagnosis. During the process of a CT scanning, noise(s) may appear in the reconstructed images. Noise(s) in uniform regions may be reduced or suppressed by performing an image denoising operation, for example, an edge preserving regularization. However, the edge preserving regularization may not reduce noise(s) on boundaries between uniform regions, making the area on the boundary between smooth surfaces appear to be rough. Thus, there is a need for a system and method to reduce the noise(s) around edges in a reconstructed image.